Rosa Joan Arguello struggled to speak after she was stricken by meningitis as a young child.

Rose ArguelloCourtesy of Thornton Police Department

“She was 5 before anyone ever understood what she was saying,” her mother Arizona Humeyumptewa-Winters said.

She had difficulty likewise learning to read and to do math in school. Her challenges spilled over into her adult life, Humeyumptewa-Winters said.

Arguello was only able to find minimum-wage jobs and often lived on the street.

She was very trusting; too trusting of the wrong types of people, Humeyumptewa-Winters said. She often bounced from homes of one undesirable acquaintance to the next.

“She was very gullible. She befriended people she shouldn’t have. She didn’t live the best life,” her mother said. “I was always worried about her out there on the street. I didn’t know how to reach her.”

Kirk Mitchell is a general assignment reporter at The Denver Post who focuses on criminal justice stories. He began working at the newspaper in 1998, after writing for newspapers in Mesa, Ariz., and Twin Falls, Idaho, and The Associated Press in Salt Lake City. Mitchell first started writing the Cold Case blog in Fall 2007, in part because Colorado has more than 1,400 unsolved homicides.